What is the Difference Between Carnot and Rankine cycle?

The Carnot cycle and Rankine cycle are both ideal heat engine cycles that describe the conversion of heat into work. However, they differ in their processes and assumptions:

Carnot Cycle:

1. Conceived by Nicolas Léonard Sadi Carnot, it is the most efficient heat engine cycle.
2. Consists of 4 processes: isothermal heat addition, isentropic compression, isothermal heat rejection, and isentropic expansion.
3. Assumes no losses and all heat is converted into work.
4. Focuses on internal energy change, dE = 0, and heat transfer, Q = W.
5. Provides the benchmark for efficiency with the Carnot efficiency formula: 1 - TC/TH (both temperatures in Kelvin).

Rankine Cycle:

1. Conceived by William John Macquorn Rankine as a practical machine that could be used in real life.
2. Involves 4 processes: isentropic compression, isobaric heat addition, isentropic expansion, and isobaric heat rejection.
3. Considers heat transfer at constant pressure instead of constant temperature.
4. Assumes some energy loss during the heat rejection process and does not maximize efficiency.
5. Allows for superheating, which increases efficiency and work output.

In summary, the Carnot cycle is an idealized process that computes the maximum efficiency achievable for a heat engine, while the Rankine cycle is a more practical approach that considers real-world constraints. The Carnot cycle focuses on isothermal heat addition and rejection, whereas the Rankine cycle assumes heat transfer at constant pressure and allows for superheating.

Comparative Table: Carnot vs Rankine cycle

The Carnot and Rankine cycles are two different thermodynamic cycles that describe the operation of heat engines. Here is a table comparing the key differences between the two cycles:

The Carnot cycle conceives a heat engine with dE = 0, where Q = W, and focuses on achieving maximum efficiency. On the other hand, the Rankine cycle works with dP = constant and is designed as a practical machine that can be used in real-life power generation. The Rankine cycle does not have the isothermal heat addition and rejection constraints of the Carnot cycle, making it a more practical option for real-world applications. As a result, the Carnot cycle has a higher work output and efficiency compared to the Rankine cycle.